Mario Balotelli could be as good a player as Cristiano Ronaldo or Lionel Messi if he learns to adjust his attitude, according to his Manchester City boss Roberto Mancini.

Balotelli faces a fitness battle to face former boss Jose Mourinho when City take on Real Madrid on Wednesday, having shared a volatile relationship with the former Chelsea coach when they were both at Inter Milan.

And Mancini admitted he shares the same frustrations the Portuguese encountered dealing with the Italian striker on a day-to-day basis.

"Mario, outside the pitch is a fantastic guy," Mancini said. "Sometimes he doesn't understand how important his job is for his life.

"I hope for him that he can understand this quickly, because now he is 22 years old.

"As a player, he could be like Cristiano [Ronaldo], [Lionel] Messi, if he understands that to be like this you should work hard. Your mind should be always on your job, not for the other things that are not important. I am very sorry for him for this.

"He can have everything, be one of the best players in the world."

Mancini admitted that working with Balotelli is a worthwhile chore, such is the striker's potential.

"It's not too easy to work with him every day, when you should manage 22 players. It is difficult sometimes, but I hope that he can change his mind."

City are rooted to the bottom of Group D but still have an outside chance of reaching the knockout stages. All four teams could feasibly end up with eight points after six games, so tight is the group that features the champions of England, Spain, Germany and Netherlands, but the Italian believes City are heading out.

"It's possible," Mancini conceded, "but I don't think that Real Madrid will not beat Ajax at home, or Dortmund.

"I think it was a difficult group when we started it, and now for us it is very difficult because probably we did some mistakes in the first two games and now it is very difficult for us.

"But we have another two games - two important games - and we want to play very well."